JP2010272906A - Radio communication device, radio communication method, and radio communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain satisfactory transmission efficiency in radio communication systems in which a plurality of mobile stations of which the number of transmission antennas differs are mixed. <P>SOLUTION: The number of transmission antennas is transmitted to a base station by control information for inputting to an antenna information acquisition section (S1). The respective mobile stations are grouped by mobile stations including one transmission antenna and mobile stations including a plurality of antennas at a priority setting section and high priority is allocated to a group including one transmission antenna (S2). Characteristic information and priority of each mobile station are inputted into a scheduling section from a propagation path characteristic estimation section and the priority setting section, respectively (S3). A transmission antenna having high priority is allocated to a group of mobile stations (S4). An unused frequency band is used for assignment in a group of mobile stations including a plurality of transmission antennas having low priority (S5). Decided assignment information is fed back to each mobile station via a control information signal generation section (S6), and is stored in a buffer for spectrum extraction in the base station (S7). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a radio communication technique, and more particularly to a scheduling technique when a terminal having a plurality of transmission antennas and a terminal having only one transmission antenna are mixed.

  In recent years, high-speed and large-capacity data transmission is desired in wireless communication systems, and researches for increasing the utilization efficiency of a limited frequency band have been actively conducted. In particular, in the uplink, there is a great limitation on the transmission power of the terminal, and it is required to achieve a high transmission rate within a limited power range.

  In this regard, in the LTE (Long Term Evolution) system, which is a wireless communication system for 3.9th generation mobile phones, PAPR (Peak to Average Power Ratio) affecting transmission power in the uplink is considered. As a transmission method that is low and that can achieve high frequency utilization efficiency, a DFT-S-OFDM (also called Discrete Fourier Transform-Spread-OFDM, SC-FDMA) method is adopted. In DFT-S-OFDM, a blocked modulation symbol sequence is converted into a frequency signal by FFT (Fast Fourier Transform), a discrete spectrum is arranged based on a specific arrangement rule, and an IFFT (Inverse FFT: By regenerating the time signal by inverse fast Fourier transform), frequency control as in the multicarrier system is possible even though it is a single carrier system.

  Further, LTE-A (also referred to as LTE-Advanced, IMT-A), which is a fourth-generation wireless communication system that is currently being standardized, further suppresses the increase in PAPR and further increases the frequency utilization efficiency. As a technique for increasing the frequency, it is decided that Clustered DFT-S-OFDM (Clustered SC-FDMA or dynamic spectrum control (DSC)) is adopted as an extension method of DFT-S-OFDM. (For example, Non-Patent Document 1. In Non-Patent Document 1, it is described as DFT-precoded OFDM, which is the same transmission method). Here, the cluster is a name for a group of a plurality of continuous subcarriers. That is, Clustered DFT-S-OFDM is obtained by dividing the frequency component of the DFT-S-OFDM signal into several clusters and rearranging them. By using this method, the frequency band can be flexibly used in accordance with the propagation path characteristics although the PAPR characteristics are slightly deteriorated as compared with DFT-S-OFDM.

  In addition, due to problems such as terminal cost, each terminal cannot perform two-antenna simultaneous transmission in the LTE uplink, but in LTE-A, MIMO (Multi-Input Multi-Output) transmission using a plurality of transmission antennas is performed. It is being considered. Among them, spatial division multiplexing (SDM) that can improve user throughput and transmission diversity that can improve transmission quality are one of technologies that are likely to be adopted.

3GPP TR 36.814 (V0.3.1) “Further Advancements for E-UTRA Physical Layer Aspects”

  In DFT-S-OFDM and Clustered DFT-S-OFDM, a frequency selective diversity effect can be obtained by dynamically allocating a discrete spectrum to a frequency with a good channel state.

  However, in the case where a plurality of mobile stations exist in the same cell, if a desired frequency is assigned to another mobile station, there may be a situation where it is unavoidable to assign a frequency having a poor propagation path condition. In particular, when a mobile station having only one transmission antenna falls into such a situation, there is a risk that transmission characteristics will be significantly degraded.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for performing scheduling with different priorities when mobile stations having different numbers of transmission antennas coexist in the same cell. .

  The wireless communication system of the present invention is a wireless communication system comprising a plurality of transmission device groups having one or more transmission antennas and a reception device having one or more reception antennas for receiving data from the transmission device group, The transmitting apparatus group includes a transmitting antenna number notifying unit that notifies the receiving apparatus of the number of transmitting antennas provided, and the receiving apparatus receives an antenna number receiving unit that receives the notification of the number of transmitting antennas. And a scheduling unit that determines allocation of radio resources based on the number of transmission antennas of each transmission apparatus.

  According to an aspect of the present invention, there is provided a wireless communication system including a plurality of transmission device groups and a reception device that receives data from the transmission device group, wherein the transmission device group receives the number of transmission antennas to be used. A transmitting antenna number notifying unit for notifying a device, wherein the receiving device allocates radio resources based on an antenna number receiving unit that receives the notification of the number of transmitting antennas and the number of transmitting antennas of each received transmitting device. A wireless communication system comprising: a scheduling unit for determining The receiving device includes a priority determining unit that determines an allocation priority according to each notified number of transmitting device antennas, a scheduling unit that determines an allocated bandwidth of the transmitting device according to the priority, and the allocated bandwidth. And a control information signal generation unit that notifies the transmission device. Preferably, the allocation priority unit assigns a group of transmission devices having one transmission antenna to a higher allocation priority than a transmission device group having another number of transmission antennas.

  The allocation priority unit may set a transmission apparatus having one transmission antenna as the highest priority, and thereafter, the priority may be lowered as the number of transmission antennas increases.

  The receiving apparatus uses an allocation weight determining unit that determines an allocation weight of each transmitting apparatus according to the notified number of transmitting apparatus antennas, and an allocation reference value of each mobile station that is weighted according to the allocated weight. It is preferable that a scheduling unit for determining the allocated band and a control information signal generating unit for notifying the transmitting apparatus of the allocated band are provided.

  The receiving apparatus preferably includes an SRS transmission period determining unit that determines an SRS transmission period according to the notified number of transmitting apparatus antennas, and the transmission period is preferably increased as the number of antennas of the transmitting apparatus increases.

  In addition, it is preferable that the receiving device includes an SRS transmission cycle determining unit that determines an SRS transmission cycle according to the determined allocation priority, and the transmission cycle becomes longer as the allocation priority becomes lower.

  The present invention includes a plurality of transmitting device groups and a receiving device that receives data from the transmitting device group, and the transmitting device group includes a transmitting antenna number notifying unit that notifies the receiving device of the number of transmitting antennas to be used. A receiving device in a wireless communication system having an antenna number receiving unit that receives the notification of the number of transmitting antennas, and a scheduling unit that determines allocation of radio resources based on the received number of transmitting antennas of each transmitting device. It is the receiver characterized by comprising. The receiving device includes a priority determining unit that determines an allocation priority according to each notified number of transmitting device antennas, a scheduling unit that determines an allocated bandwidth of the transmitting device according to the priority, and the allocated bandwidth. And a control information signal generation unit that notifies the transmission device.

  Preferably, the allocation priority unit assigns a group of transmission devices having one transmission antenna to a higher allocation priority than a transmission device group having another number of transmission antennas. The allocation priority unit preferably sets the transmission apparatus having one transmission antenna as the highest priority, and lowers the priority as the number of transmission antennas increases. An allocation weight determining unit that determines an allocation weight of each transmitting apparatus according to the notified number of transmitting apparatus antennas, and an allocation reference value of each mobile station that is weighted according to the allocated weight is used to determine an allocated band of the transmitting apparatus And a control information signal generation unit that notifies the transmission apparatus of the allocated band. It is preferable that an SRS transmission cycle determining unit that determines a transmission cycle of the SRS is provided according to the notified number of transmitting device antennas, and the transmission cycle becomes longer as the number of antennas of the transmitting device increases. An SRS transmission period determining unit that determines an SRS transmission period according to the determined allocation priority order may be provided, and the transmission period may be longer as the allocation priority order is lower.

  A radio resource allocation is determined based on a plurality of transmitting device groups and an antenna number receiving unit that receives data from the transmitting device group and receives the notification of the number of transmitting antennas, and the received number of transmitting antennas of each transmitting device. A transmission apparatus in a wireless communication system including a scheduling unit and a reception apparatus including the transmission apparatus group, wherein the transmission apparatus group includes a transmission antenna number notifying unit that notifies the reception apparatus of the number of transmission antennas to be used. Is provided.

  According to another aspect of the present invention, there is provided a communication method in a wireless communication system including a plurality of transmission device groups and a reception device that receives data from the transmission device group, wherein the transmission device group includes a transmission antenna to be used. A number of transmitting antennas notifying step of notifying the number of transmission antennas to the receiving device, the receiving device based on the number of antennas receiving step of receiving the notification of the number of transmitting antennas, and the number of transmitting antennas of each transmitting device received, And a scheduling method for determining allocation of radio resources. It may be a program for causing a computer to execute the method, or a computer-readable recording medium for recording the program. The program may be acquired by a transmission medium such as the Internet.

  According to the present invention, by preferentially allocating to a mobile station that is susceptible to propagation path characteristics and has a small number of antennas, it is possible to suppress degradation of transmission characteristics and improve cell throughput.

It is a figure which shows the concept of the communication technique by embodiment of this invention. FIG. 2 is a functional block diagram illustrating a configuration example of a mobile station apparatus, which is a configuration example of a transceiver according to the first embodiment of the present invention. It is a functional block diagram which shows the example of 1 structure of the base station apparatus used as a receiver. It is a flowchart figure which shows the operation | movement in the scheduling part periphery (structure in the broken-line part of FIG. 3). It is a flowchart figure which shows the flow of the process by the 2nd Embodiment of this invention. It is a flowchart figure which shows the flow of the scheduling process in the 3rd Embodiment of this invention. FIG. 4 is a diagram corresponding to FIG. 3, and is a diagram illustrating a configuration example in consideration of antenna number information notified by a mobile station in addition to a conventional period determination reference. It is a figure which shows the structural example which considered the allocation priority determined in the time of scheduling instead of the number of antennas from the relative relationship of all the mobile stations.

  Hereinafter, a communication technique according to each embodiment of the present invention will be described with reference to the drawings. In each of the following embodiments, unless otherwise specified, the description is made for communication on the uplink, which is communication from a mobile station to a base station, which is generally referred to. The target communication is not limited to uplink communication.

[First Embodiment] (Assigned from a user with one antenna in SC)
FIG. 1 is a diagram showing a concept of communication technology according to the present embodiment. Here, an example of the outline of the wireless communication system is shown. In FIG. 1, as a wireless communication system, a first mobile station 1 having one transmission antenna and a second mobile station 2 having a plurality of transmission antennas (two examples are shown in the figure). And a base station 3 having a plurality of receiving antennas (two examples are shown in the figure). In this embodiment, it is assumed that the transmission scheme is the DFT-S-OFDM scheme, but the transmission scheme may be used for different transmission schemes such as the Clustered DFT-S-OFDM scheme and the OFDM scheme.

  Here, assuming that MIMO transmission (spatial multiplexing, transmission diversity, etc.) using a plurality of transmission / reception antennas is performed, the propagation path for transmitting the signal of each mobile station is (number of transmission antennas) × (reception antennas) There will be as many as the number). In this case, since the second mobile station 2 has a larger number of antennas than the first mobile station 1, the number of paths between the mobile stations 1 and 2 and the base station 3 is increased, and the overall average propagation is increased. The road characteristics become more stable. In other words, the first mobile station 1 is more susceptible to frequency selective fading, and the second mobile station 2 has a frequency band with a channel characteristic that has a poorer spectrum than the first mobile station 1. Is unlikely to be assigned.

  Based on the above points, an example in which two mobile stations 1 and 2 perform allocation to continuous frequencies using the DFT-S-OFDM transmission system is shown in FIGS. Yes. However, the propagation path characteristics shown here are substantial propagation path characteristics calculated from the entire propagation paths for the number of antennas. When assigned in order from the first mobile station 1, as shown in FIG. 1B, the first mobile station 1 can occupy a frequency band with particularly high propagation path characteristics. The second mobile station 2 to be assigned next is assigned to the frequency band having an average characteristic because the propagation path characteristic is relatively stable. As a result, the two mobile stations 1 and 2 can perform transmission at a position having a relatively high average propagation path characteristic. On the other hand, when the mobile stations are assigned in order from the second mobile station 2, the second mobile station 2 is assigned to a frequency band having slightly higher propagation path characteristics as shown in FIG. However, since the first mobile station 1 to be assigned next is occupied by the second mobile station 2 with a frequency band having good characteristics, it must be assigned to a position with significantly deteriorated characteristics. As a result, the propagation path characteristics of the allocated bands of all the mobile stations are deteriorated as compared with the case of FIG. That is, in this case, it is understood that the characteristics can be improved by assigning from the first mobile station 1.

  Thus, in the present embodiment, when the transmission method is DFT-S-OFDM, and the number of antennas is one when a mobile station with a single transmission antenna and a plurality of mobile stations are mixed in the same cell, the number of antennas is One mobile station performs the allocation first.

  Based on the above concept, a case where a large number of mobile stations actually exist in the same cell will be described. At this time, it is classified into a mobile station group A having one transmission antenna and a mobile station group B having a plurality of transmission antennas. Then, a scheduling method such as Proportional Fairness (PF) is applied to group A, and the allocated bandwidth of all mobile stations in group A is determined. Thereafter, scheduling is similarly performed for the group B, and allocation is performed for the frequency band not occupied by the group A. By performing the assignment in such a procedure, it is possible to avoid that all mobile stations are assigned to frequency bands having extremely poor characteristics. Here, the scheduling after classification into groups may be different, such as Maximum Carrier to Interference power Ratio (Max CIR) or Round Robin (RR).

  Next, a configuration example of the transceiver according to this embodiment will be described. FIG. 2 is a functional block diagram illustrating a configuration example of the mobile station apparatus. FIG. 2 shows the case where the number of antennas of the mobile station is 2 and the number of codewords is 2. In the present invention, regardless of this condition, the number of antennas is different from this, or the number of codewords is different. But the same operation is performed.

  The transmission bit sequences that are parallelized according to the number of codewords are first sent to the first and second error correction coding units 1a and 1b (hereinafter, descriptions of the first and second are omitted). Entered. The error correction encoding units 1a and 1b perform error correction encoding such as a convolutional code or a turbo code on the input data bit sequence. At this time, interleaving may be performed. The obtained encoded bit sequence is then modulated by the modulation units 2a and 2b and input to the DFT units 3a and 3b. In the DFT units 3a and 3b, DFT (Discrete Fourier Transform) is performed on the modulation symbols and converted into frequency domain signals. On the other hand, the control information transmitted from the base station apparatus is input to the spectrum allocation information detection unit 5 to obtain spectrum allocation information. This allocation information is input to the spectrum allocation units 4a and 4b for each antenna, and mapping of each frequency domain signal spectrum is performed. The frequency domain signal after mapping is converted again into a time domain signal in the IDFT units 6a and 6b. A CP (Cyclic Prefix) is added to each antenna in the CP adding units 7a and 7b, and is input to the reference signal multiplexing units 8a and 8b. In the reference signal multiplexing units 8a and 8b, the reference signal generation unit 9 multiplexes the reference signal generated according to the control information from the base station, forms a frame, and inputs the frame to the radio units 10a and 10b. The radio units 10a and 10b perform processing such as DA (Digital to Analog) conversion, up-conversion, and band-pass filtering on the input digital signal, and then transmit from the antenna units 11a and 11b.

  FIG. 3 is a functional block diagram illustrating a configuration example of a base station apparatus serving as a receiver. Signals received by the antenna units 101a and 101b are input to the radio units 102a and 102b. The radio units 102a and 102b perform down conversion, filtering processing, and AD (Analog to Digital) conversion. In the reference signal separation sections 103a and 103b, the reference signal is separated from the output signal, the reference signal is input to the propagation path estimation section 104, and the received signal after separation is input to the CP removal sections 105a and 105b. The propagation path estimation unit 104 estimates propagation path characteristics from the input reference signal, and sends this information to the scheduling unit 109 and the equalization unit 112. The operation of the scheduling unit 109 will be described later. On the other hand, the received signal after separation is subjected to DFT conversion in the DFT units 106a and 106b into frequency domain signals after the CP is removed by the CP removing units 105a and 105b. Based on the scheduling information stored in the buffer 107, the signal spectrum of the frequency band used by each mobile station is extracted from the frequency domain signal and input to the equalization unit 112. The equalizer 112 uses the propagation path information to perform frequency domain equalization, and at the same time, separates signals transmitted from each transmission antenna in MIMO transmission. The signals after the signal separation are respectively input to the number of IDFT units 113a and 113b corresponding to the number of codewords, converted into time domain signals again, and then demodulated based on the modulation performed by the transmitters in the demodulation units 114a and 114b. Is done. Furthermore, after deinterleaving is performed as necessary, the transmitted information bit sequence is obtained by performing error correction decoding processing in the decoding units 115a and 115b.

  Here, the operation in the vicinity of the scheduling unit 109 (configuration in the broken line portion in FIG. 3) will be described with reference to the flowchart in FIG. In the scheduling unit 109, the frequency band assigned to each mobile station serving as a transmission apparatus is determined. In the present invention, the frequency band is determined mainly based on the antenna number information and the propagation path characteristics (step S1). The number of transmission antennas used in the transmitter is transmitted to the base station by control information and input to the antenna information acquisition unit 100. Thereafter, in the priority setting unit 108, each mobile station is grouped into one mobile station and a plurality of mobile stations (step S2), and a high priority is assigned to the group of one transmission antenna. The scheduling unit 109 receives the characteristic information from the propagation path characteristic estimation unit (step S3), the priority setting unit 108 receives the priority of each mobile station, and the transmission antenna having a high priority is one mobile station group. Is allocated (step S4), and thereafter, allocation is performed in a mobile station group having a plurality of transmission antennas with low priorities using a free band (step S5). The determined allocation information is fed back to each mobile station via the control information signal generator 110 (transmission: step S6) and stored in a buffer for spectrum extraction at the base station (step S7).

  In this embodiment, the number of antennas whose propagation path characteristics are likely to become unstable is allocated from a single mobile station, thereby preventing each mobile station from being assigned to a propagation path with significantly poor characteristics, and as a result, The cell throughput can be improved.

[Second Embodiment] (Assignment with different priorities for each number of antennas)
In the first embodiment described above, an example has been described in which allocation is performed in order for a mobile station with one transmission antenna and a plurality of mobile stations. However, it has been found that the propagation path characteristics between the mobile station and the base station become more stable as the number of transmission antennas increases. Therefore, in this embodiment, a higher priority is assigned to a mobile station having a smaller number of transmission antennas, and assignment is performed in order.

  FIG. 5 is a flowchart showing the flow of processing according to this embodiment. The transceiver configuration is the same as that in FIGS. 2 and 3 in the first embodiment. In accordance with the antenna number information notified by the mobile station (step S11), the base station groups each mobile station for each transmission antenna number (step S12), and sets the number of transmission antennas as a priority in each group (step S13). ). Then, according to the propagation path characteristic obtained by propagation path estimation (step S14), allocation is performed in order from the group with the lowest priority (steps S14 to S18). After the assignment of all mobile stations in all groups is completed, the assignment information is transmitted as control information to each mobile station (step S19) and stored in the buffer in parallel (step S20). Here, the number of transmitting antennas is used as it is as the priority order, but any value may be used as long as the order of assignment does not change.

  In this embodiment, scheduling is more complicated than in the first embodiment, but it is possible to further suppress the occurrence probability of mobile stations assigned to propagation paths with poor characteristics.

[Third Embodiment] (We assign weights by the number of antennas and assign them simultaneously)
Next, a third embodiment of the present invention will be described. The present embodiment relates to scheduling in a radio communication system in which a plurality of mobile stations having different numbers of antennas are mixed, and the transmission system assumes the Clustered DFT-S-OFDM system, but the DFT-S-OFDM system is assumed. It may also be used for the OFDM system or the like.

  In the Clustered DFT-S-OFDM system, unlike the DFT-S-OFDM system, the frequency spectrum of each mobile station does not need to be arranged in a continuous frequency band, and can be arranged in a discrete frequency band for each cluster. Become. As a result, mobile stations do not allocate the entire spectrum at once, but different mobile stations can alternately allocate clusters, enabling flexible scheduling to achieve high transmission characteristics while maintaining fairness among mobile stations. It becomes.

  On the other hand, when mobile stations with different numbers of transmission antennas coexist, as described in the first embodiment, the mobile station with a small number of antennas is likely to deteriorate the propagation path characteristics, and the cluster is assigned later in the order in scheduling. If this happens, the transmission quality will deteriorate.

  In view of the above, in this embodiment, in order to maintain a high scheduling priority for a mobile station with a small number of antennas while maintaining flexible scheduling, the number of transmission antennas of the mobile station is set to the scheduling allocation criterion. The weight shall be based on.

  When scheduling such as PF and MAX CIR is performed for a mobile station with multiple antennas, the allocation reference value is propagation of average received SINR (Signal to Interference and Noise power Ratio), CQI (Channel Quality Indicator), communication channel capacity, etc. Road characteristics are used. For example, when PF is performed using the average received SINR, a cluster is allocated to a mobile station in which the ratio of the instantaneous SINR in the frequency bandwidth corresponding to the cluster size and the average SINR over the entire frequency band is maximized. .

は、

となる。 In the conventional method, a mobile station that can assign a cluster to the i-th frequency band

Is

It becomes.

は第u番目の移動局のi番目の周波数帯域における割当基準値である。
本実施の形態では、各移動局の送信アンテナ本数に従い割当基準値に重みを付ける。 here

Is an allocation reference value in the i-th frequency band of the u-th mobile station.
In this embodiment, the allocation reference value is weighted according to the number of transmission antennas of each mobile station.

  Here, α (i) is a weight depending on the number of transmission antennas of the i-th mobile station, and a larger value is used as the mobile station has a smaller number of antennas. While assigning priority to mobile stations with a small number of transmitting antennas by weighting in this way, the characteristics of a mobile station with a small number of antennas are poor and the characteristics of a mobile station with a large number of antennas are clearly good. It becomes possible to respond to the occasion in the situation where it exists.

  FIG. 6 is a flowchart showing the flow of scheduling processing in the present embodiment. As in the first and second embodiments, grouping is performed for each number of antennas based on the antenna number information transmitted from each mobile station. A weight α corresponding to the priority order according to the number of antennas is given, and the scheduling unit simultaneously performs scheduling in all mobile stations using the propagation path characteristic multiplied by the weight α (steps S25 to S26). Other processing procedures are the same as in the above example. Thereafter, the allocation information is transmitted to each mobile station and further stored in a buffer for spectrum extraction of the received signal.

  In this embodiment, weighting is performed based on the number of antennas, and allocation is given to all mobile stations at the same time, so that allocation priority is given to mobile stations with a small number of antennas while performing flexible scheduling for the system band. As a result, high cell throughput can be obtained.

[Fourth Embodiment] (Reduction of SRS frequency of later mobile stations)
Similar to the first to third embodiments, this embodiment gives high allocation priority to mobile stations with a small number of transmission antennas, and scheduling is performed for mobile stations with a large number of transmission antennas. The amount of data transmission can be increased by reducing the transmission frequency of the sounding reference signal (SRS) used for the propagation path estimation.

  As a concept in the first and second embodiments, the stability of the propagation path characteristics used for allocation is improved as the number of antennas is increased. In other words, a relatively high transmission characteristic can be obtained for a multi-antenna mobile station as compared with a mobile station with a small number of antennas, regardless of the frequency band to which a spectrum is assigned. Furthermore, setting the priority to a low level means that there is a high possibility that the allocation is determined without depending much on the allocation reference value. Therefore, a mobile station with a large number of antennas does not require highly accurate propagation path information compared to a mobile station with a small number of antennas. Here, a known reference signal called SRS is used for grasping propagation path characteristics necessary for allocation. Since the propagation path changes on the time axis according to the movement of the mobile station and the surrounding situation, the more accurate the SRS is obtained, the more accurate the radio path information is obtained. You will be pressured. Therefore, the transmission frequency of the SRS is transmitted at a period that does not impose data transmission while obtaining a certain degree of accuracy.

  In view of the above, in the present embodiment, due to the difference in accuracy of required propagation path characteristics, the SRS transmission cycle of a mobile station with a large number of transmission antennas with a low allocation priority is shortened, and the mobile station with a small number of transmission antennas is lengthened. It is characterized by.

  The transmission period of SRS is determined based on propagation path fluctuation measured by propagation path estimation by a normal base station. For example, one subframe is composed of several symbols as a minimum unit, and one SRS is multiplexed every period of 1 subframe to 10 subframes. In the present embodiment, as shown in FIG. 7 corresponding to FIG. 3, in addition to the conventional period determination criterion, the number of antennas information notified by the mobile station is also considered. As an example, it is assumed that there is a mobile station that transmits an SRS every two subframes. In this embodiment, when the number of transmission antennas is one, this mobile station similarly transmits every two subframes. However, when the number of antennas is two, the substation is doubled by four subframes. Is the transmission cycle. That is, the SRS transmission cycle determination unit 121 obtains SRS transmission cycle information from the propagation path information from the propagation path estimation unit 104 and the antenna information from the antenna information acquisition unit 100, and sends this to the control signal generation unit 110. However, in actuality, the transmission period may be changed based on the number of antennas, and the numerical value may change according to the required transmission quality. Further, from the relative relationship among all mobile stations, as shown in FIG. 8, it may be based not on the number of antennas but on the allocation priority determined at the time of scheduling (information from the priority setting unit 108).

[Fifth embodiment] (Fractional TPC-aware scheduling method)
As a fifth embodiment, a scheduling method considering transmission power control called fractional TPC will be described. Fractional TPC is transmission power control that limits transmission power to a mobile station at the end of a cell in consideration of interference with adjacent cells. Therefore, when such transmission power control is adopted, if SIMO is simply given priority, if the mobile station with cell edge SIMO is given priority, the assignment of mobile stations with lower transmission power is given priority. As a result, the cell throughput may be reduced. On the other hand, in the case of MIMO, if a technique such as transmission diversity is used at the cell edge, a desired reception SNR is lowered, so that communication may be possible. Therefore, the area covered by each base station is divided into, for example, three areas according to the distance of the base station, and scheduling is performed to give priority to SIMO terminals in each area, and in the case of SIMO and MIMO existing in the cell edge area Lowers the priority of SIMO (decreases the weight). By changing the priority according to the area, it is possible to perform efficient scheduling considering the cell throughput.

  The classification of each mobile station may be calculated from received SINR by SRS or using PH (Power Headroom) indicating how much transmission power is available.

  In the present embodiment, when fractional TPC is used, areas are divided according to the distance from the base station, and the priority of SIMO mobile stations is changed for each area, so that SIMO mobility with poor conditions is performed. It is possible to prevent the station from being given priority unfairly, and as a result, it is possible to increase the cell throughput.

  According to the present invention, by preferentially allocating to a mobile station that is susceptible to propagation path characteristics and has a small number of antennas, it is possible to suppress degradation of transmission characteristics and improve cell throughput.

  In the above-described embodiment, the configuration and the like illustrated in the accompanying drawings are not limited to these, and can be changed as appropriate within the scope of the effects of the present invention. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  In addition, a program for realizing the functions described in the present embodiment is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed to execute processing of each unit. May be performed. The “computer system” here includes an OS and hardware such as peripheral devices.

  Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.

  The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the above-described functions, or may be a program that can realize the above-described functions in combination with a program already recorded in a computer system.

  The present invention can be used for a wireless communication apparatus.

DESCRIPTION OF SYMBOLS 1a, 1b ... 1st and 2nd error correction encoding part, 2a * 2b ... Modulation part, 3a * 3b ... DFT part, 4a * 4b ... Spectrum allocation part, 5 ... Spectrum allocation information detection part 5, 6a * 6b ... IDFT part, 7a and 7b ... CP addition part, 8a and 8b ... Reference signal multiplexing part, 9 ... Reference signal generation part, 10a and 10b ... Radio part, 11a and 11b ... Antenna part, 101a and 101b ... Antenna part, 102a 102b: wireless unit 103a 103b reference signal separating unit 104 propagation path estimating unit 105a 105b CP removing unit 106a 106b DFT unit 107 buffer 109 scheduling unit 112 equalizing 113a, 113b, IDFT, 114a, 114b, demodulator, 115a, 115b, decoder.

Claims (18)

A wireless communication system comprising a plurality of transmitting device groups and a receiving device that receives data from the transmitting device group,
The transmitting device group includes a transmitting antenna number notifying unit that notifies the receiving device of the number of transmitting antennas to be used.
The receiving apparatus includes an antenna number receiving unit that receives the notification of the number of transmitting antennas,
A scheduling unit that determines allocation of radio resources based on the number of transmission antennas of each transmission device received;
A wireless communication system comprising: The receiving device is:
A priority determining unit that determines an allocation priority according to the notified number of transmitting device antennas;
A scheduling unit for determining an allocated bandwidth of the transmission device according to the priority order;
A control information signal generation unit for notifying the transmission apparatus of the allocated bandwidth;
The wireless communication system according to claim 1, further comprising: The allocation priority part is:
3. The wireless communication system according to claim 2, wherein a group of transmission apparatuses having one transmission antenna is assigned a higher priority for assignment than a transmission apparatus group having another number of transmission antennas. The allocation priority part is:
3. The wireless communication system according to claim 2, wherein the transmission apparatus having one transmission antenna is set to the highest priority, and thereafter, the priority is lowered as the number of transmission antennas increases. The receiving device is:
An allocation weight determining unit that determines an allocation weight of each transmitting apparatus according to the notified number of transmitting apparatus antennas;
A scheduling unit for determining an allocation band of the transmission device using an allocation reference value of each mobile station weighted according to the allocation weight;
A control information signal generation unit for notifying the transmission apparatus of the allocated bandwidth;
The wireless communication system according to claim 1, further comprising: The receiving device is:
In accordance with each notified number of transmitting device antennas, an SRS transmission period determining unit that determines an SRS transmission period is provided.
6. The wireless communication system according to claim 1, wherein the transmission cycle becomes longer as the number of antennas of a transmission apparatus increases. The receiving device is:
An SRS transmission period determining unit that determines an SRS transmission period according to the determined allocation priority;
The wireless communication system according to claim 3 or 4, wherein the transmission cycle becomes longer as the allocation priority becomes lower. Wireless communication having a plurality of transmitting device groups and a receiving device that receives data from the transmitting device group, wherein the transmitting device group includes a transmitting antenna number notifying unit that notifies the receiving device of the number of transmitting antennas to be used. A receiving device in the system,
An antenna number receiving unit for receiving the notification of the number of transmitting antennas;
A scheduling unit that determines allocation of radio resources based on the number of transmission antennas of each transmission device received;
A receiving apparatus comprising: The receiving device is:
A priority determining unit that determines an allocation priority according to the notified number of transmitting device antennas;
A scheduling unit for determining an allocated bandwidth of the transmission device according to the priority order;
A control information signal generation unit for notifying the transmission apparatus of the allocated bandwidth;
The receiving apparatus according to claim 8, comprising: The allocation priority part is:
The receiving apparatus according to claim 9, wherein a group of transmitting apparatuses having one transmitting antenna has a higher allocation priority than a transmitting apparatus group having other transmitting antennas. The allocation priority part is:
The receiving apparatus according to claim 9, wherein the transmitting apparatus having one transmitting antenna is set to have the highest priority, and the priority is lowered as the number of transmitting antennas increases. An allocation weight determining unit that determines an allocation weight of each transmitting apparatus according to the notified number of transmitting apparatus antennas;
A scheduling unit for determining an allocation band of the transmission device using an allocation reference value of each mobile station weighted according to the allocation weight;
A control information signal generation unit for notifying the transmission apparatus of the allocated bandwidth;
The receiving apparatus according to claim 8, comprising: In accordance with each notified number of transmitting device antennas, an SRS transmission period determining unit that determines an SRS transmission period is provided.
The receiving apparatus according to any one of claims 8 to 12, wherein the transmission cycle becomes longer as the number of antennas of the transmitting apparatus increases. An SRS transmission period determining unit that determines an SRS transmission period according to the determined allocation priority;
The receiving apparatus according to claim 10 or 11, wherein the transmission cycle becomes longer as the allocation priority becomes lower. A radio resource allocation is determined based on a plurality of transmitting device groups and an antenna number receiving unit that receives data from the transmitting device group and receives the notification of the number of transmitting antennas, and the received number of transmitting antennas of each transmitting device. A transmission device in a wireless communication system comprising a scheduling unit and a reception device comprising:
The transmitting apparatus group includes transmitting antenna number notifying means for notifying the receiving apparatus of the number of transmitting antennas to be used. A communication method in a wireless communication system comprising a plurality of transmission device groups and a reception device that receives data from the transmission device group,
The transmitting device group includes a transmitting antenna number notifying step of notifying the receiving device of the number of transmitting antennas to be used.
The receiving device comprises: an antenna number receiving step for receiving the notification of the number of transmitting antennas; and a scheduling step for determining radio resource allocation based on the received number of transmitting antennas of each transmitting device. Communication method.   A program for causing a computer to execute the method according to claim 16.   A computer-readable recording medium for recording the program according to claim 17.

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